ANGINA TREATMENT OVERVIEW

Chest pain that originates from the heart is called “angina pectoris.” Angina is a signal that the heart muscle is not getting sufficient blood flow, specifically sufficient oxygen. Lack of oxygen is termed “ischemia.” Blood flow is most often reduced by coronary artery disease, which causes a narrowing of the arteries that carry blood to the heart muscle. Narrowing in the coronary arteries occurs as a result of calcium and fatty deposits, called plaques. In more severe cases, heart attack (myocardial infarction), heart failure, or rhythm abnormalities can cause sudden cardiac death.

Angina may be provoked by an activity or exercise or any other physical or mental stress that increases the heart’s demand for blood. Angina can be “stable” or “unstable.” Angina is unstable when there is a change in the usual pattern, such as a change in frequency, occurrence with less exertion, or occurrence at rest. Unstable angina, which may or may not be associated with damage to the heart muscle (or heart attack), is called acute coronary syndrome and requires immediate evaluation in a hospital

NITRATES

Nitrates improve blood flow by relaxing and dilating (expanding) veins and arteries, including the coronary arteries. They reduce the amount of blood returning to the heart, which may be helpful for patients with heart failure. Several different nitrate preparations are available.

Sublingual nitroglycerin — Sublingual (under the tongue) nitroglycerin (NTG) is usually recommended to treat sudden attacks of angina and to prevent angina while engaging in activities that typically trigger angina, such as mowing the lawn, playing sports, or walking up a hill (especially in the cold).

Sublingual NTG is a small pill that is placed under the tongue where it rapidly dissolves and is absorbed. The membranes underneath the tongue must be moist to facilitate this process, so a drink of water before the pill is recommended to moisten a dry mouth. Sublingual NTG becomes effective within two to five minutes and its effects last 15 to 30 minutes. NTG pills do not have any explosive potential.

Oral nitrates — Oral nitrates have a longer-lasting effect than sublingual NTG and are equally effective in controlling angina on a chronic basis. Oral nitrates are available in two forms: isosorbide dinitrate (ISDN) and isosorbide-5-mononitrate (ISMN).

Transdermal nitroglycerin — Transdermal NTG (NTG patch) is a convenient type of long-lasting nitrate treatment. These patches deliver a constant dose of NTG.

Transdermal NTG begins acting within 30 minutes and its effects last for 8 to 14 hours. Wearing a patch continuously leads to tolerance, so patches must be removed each day to allow for a “nitrate-free” interval. Since most people experience angina with activity, the patch is usually applied in the morning and removed in the evening. By contrast, people who have nocturnal (nighttime) angina should apply the patches at night and remove them in the morning.

BETA BLOCKERS

Beta blockers reduce the heart rate, blood pressure, and the force of the heart’s contractions, thereby decreasing the amount of oxygen the heart requires to pump blood. Along with nitrates, beta blockers are usually the first choice for the treatment of stable angina, and they are particularly beneficial in people who have angina during exercise or activity.

Another important benefit of beta blockers is that they improve survival and prevent another heart attack in people who have suffered a recent heart attack.

Most beta blockers are available as a long-acting preparation that is taken once per day.

CALCIUM CHANNEL BLOCKERS

Calcium channel blockers dilate arteries, decrease the force of the heart’s contractions, and lower blood pressure. They also dilate veins, reducing the amount of blood returning to the heart, which reduces the workload of the heart. Some calcium channel blockers slow the heart rate, which also reduces the work of the heart.

Dihydropyridines — The dihydropyridine calcium channel blockers include amlodipine, felodipine, nifedipine, nicardipine, and nitrendipine. These work to dilate blood vessels; this effect is greater for dihydropyridines than for other classes of calcium channel blockers. They also slightly decrease the strength of the heart’s contractions. Dihydropyridines have little effect on the conduction of electrical impulses in the heart.

Verapamil — Verapamil slows the heart’s conduction of electrical impulses, decreases the force of the heart’s contractions, and dilates blood vessels. Although it is less effective than beta blockers for slowing the heart rate, it is a safe and effective alternative; the choice between beta blockers and calcium channel blockers depends upon individual factors. Verapamil is effective for variant (vasospastic) angina. Verapamil is available in sustained release form, which is taken once per day.

Side effects – Constipation is the major side effect of verapamil, occurring in over 25 percent of people taking the medication. Other side effects are similar to those occurring with the dihydropyridines, although peripheral edema (swelling of the extremities) is uncommon.

Depression of cardiac function is a concern with verapamil. Verapamil decreases the force of the heart’s contractions and slows its conduction of electrical impulses. These effects can produce a pronounced slowing of heart rate, heart block (impaired electrical conduction in the heart), and worsening of heart failure. Verapamil must be used cautiously or avoided in people with cardiac conditions such as sick sinus syndrome and atrioventricular block. It is generally not used in combination with beta blockers.

Diltiazem — The effects of diltiazem lie between those of the dihydropyridines and those of verapamil, neither markedly dilating blood vessels nor markedly depressing cardiac function. Diltiazem dilates blood vessels (especially coronary arteries), decreases the heart’s force of contraction, and slows the heart’s conduction of electrical impulses.

Diltiazem may be preferable because it causes fewer side effects. Diltiazem is available in sustained release form that is taken once per day.

Side effects – When compared with dihydropyridines and verapamil, diltiazem has a lower frequency of side effects and has a more balanced effect, neither markedly dilating blood vessels nor markedly depressing cardiac function.

ASPIRIN

Heart attacks are usually the result of a blood clot forming inside a narrowed coronary artery. Aspirin helps to prevent these clots from forming and can therefore lower the risk of a heart attack. Health care providers often recommend daily aspirin for people with stable angina